[AWS::OpenSearchService::Domain] - [Coverage] - Dedicated coordinator nodes support

### Name of the resource

AWS::OpenSearchService::Domain

### Resource name

_No response_

### Description

AWS OpenSearch recently introduced the option to setup dedicated 'coordinator nodes':
- https://docs.aws.amazon.com/opensearch-service/latest/developerguide/Dedicated-coordinator-nodes.html
- https://aws.amazon.com/blogs/big-data/improve-opensearch-service-cluster-resiliency-and-performance-with-dedicated-coordinator-nodes/

However the `AWS::OpenSearchService::Domain` resource does not seem to support this new feature yet:
- https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-opensearchservice-domain-clusterconfig.html

Looking at the API, the option for configuring this is nested under `ClusterConfig/Options/NodeOptions`:
- https://docs.aws.amazon.com/opensearch-service/latest/APIReference/API_UpdateDomainConfig.html
- https://docs.aws.amazon.com/opensearch-service/latest/APIReference/API_NodeOption.html

### Other Details

_No response_

Start with the AWS::OpenSearchService::Domain ClusterConfig documentation and compare it with the UpdateDomainConfig and NodeOption API references linked in the issue. Confirm the required CloudFormation property shape and validation for dedicated coordinator nodes; done means the resource exposes and supports that configuration consistently with the API.

Written by the indexing model from the issue text.